1. Field of the Invention
This invention relates to a spring-driven reel for maintaining a line, cable or the like under tension and free of slack as the effective length of the line or cable varies. More particularly, this invention relates to an elongated helical spring which is compressed when the line or cable is unwound from the spool of the device with the compressed spring rotating the spool in a winding manner to wind the line or cable upon the spool as the effective length of the line or cable is shortened.
2. Description of the Related Art
Many types of spring-driven reels have been previously provided for use with cranes, hoists, etc., which employ lines or cables which supply electrical power to a traveling object. As the object is moved away from the reel, the line or cable is unwound from the spool of the reel. As the object is moved towards the reel, the spring rotates the spool to wind the line or cable onto the spool. In the past, most springs were of the “clock” type. Although the “clock” type springs do function well, the life thereof is rather limited which requires extensive disassembly of the reel to replace the spring.
In an effort to overcome the shortcomings of the “clock” type springs, elongated helical or linear springs have been substituted for the “clock” type springs. U.S. Pat. No. 2,303,002 to Ruddock discloses an elongated helical spring which has one end thereof fixed to a support with the other end being rotated to twist the spring into tension as the line is pulled from the spool by the object moving away from the reel. When the object is moved towards the reel, thereby causing slack in the line, the twisted spring unwinds to rotate the spool to wind the line onto the spool. In U.S. Pat. No. 2,645,432, an improvement to the reel of U.S. Pat. No. 2,303,002 is disclosed.
In both of the designs of the aforementioned patents, the rotational twisting of the helical springs eventually causes the spring to fail.